1. Field
The present disclosure relates to novel energy absorption material, and in particular to absorb sound energy and to provide a shield or sound barrier. More specifically, the present disclosure relates to a dark acoustic metamaterial to act as a sound absorption system even though the system is geometrically open.
2. Background
The attenuation of low frequency sound has been a challenging task because the dynamics of dissipative systems are generally governed by the rules of linear response, which dictate the frictional forces and fluxes to be both linearly proportional to rates. It follows that the dissipative power is quadratic in rates, thereby accounting for the inherently weak absorption of low frequency sound waves by homogeneous materials. To enhance the dissipation at low frequencies it is usually necessary to increase the energy density inside the relevant material, e.g., through resonance.